Metrics in Kubernetes

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Internal

Overview

Resource

Metrics

Resource Metrics

A resource metric is a numeric quantity that tracks either the CPU or memory consumed by containers and pods. By default, the only two supported resource metrics are the CPU utilization and the memory consumed by a container. These resources do not change names from cluster to cluster and they should be available as long the Resource Metrics API is available.

Resource Metrics API

metrics.k8s.io TODO:

Custom Metrics

Aside from resource metrics, there are two other types of metrics, both of which are considered custom metrics: pod metrics and object metrics. Custom metrics track resources used by Kubernetes objects (pods or otherwise).

Pod Metrics

Pod metrics track resources that describe pods.

Object Metrics

Object metrics track resources describe different objects in the same namespace, instead of describing pods.

Custom Metrics API

custom.metrics.k8s.io

Monitoring systems like Prometheus expose application-specific metrics to the Horizontal Pod Autoscaler controller via the Custom Metrics API.

External Metrics

External Metrics API

external.metrics.k8s.io

Sources of Metrics

Kubernetes Metrics Server

Kubernetes Metrics Server

Prometheus

Prometheus

Metric Pipeline

Resource metrics pipeline: https://kubernetes.io/docs/tasks/debug-application-cluster/resource-usage-monitoring/#resource-metrics-pipeline

Full metrics pipeline: https://kubernetes.io/docs/tasks/debug-application-cluster/resource-usage-monitoring/#full-metrics-pipeline

Notes